From left Jaeger-LeCoultre, Chrono Shark, ref. E2643. Estimate $7,000-12,000. Cartier, 18k Tortue monopusher chronograph, ref. 2396. Estimate $10,000-15,000. Omega, Speedmaster ‘Ed White’,

7 desirable watches from The Keystone Collection

A closer look at the details and histories that make these watches — offered in an online sale — so appealing

Rolex Daytona ref. 6241 with tropical ‘Paul Newman’ dial

In just over five decades, the Daytona has become the world’s leading sports chronograph, with vintage ‘Paul Newman’ variants leading in terms of desirability.

Certain Newman Daytonas are more sought after than others, and this example ticks many boxes. A rare ref. 6241, of which only 3,000 examples are estimated to have been produced, it is fitted with the striking combination of pump pushers and a black acrylic bezel.

Daytona collectors will be excited to see that after years of exposure to the elements the dial on this watch has achieved a ‘tropical’ tone, consistent with other examples of the era. If you value rarity, honesty and originality, this execution of the Paul Newman Daytona is definitely one to follow.

Jaeger LeCoultre ref. E2643 Shark Deep Sea

Chronographs aren’t necessarily the first topic when discussing vintage Jaeger LeCoultre, but there are several references worthy of closer consideration, such as the ref. E2643, the ‘Shark Deep Sea’.

The Shark Deep Sea, as it is known to Americans, was marketed throughout Europe as both the ‘Vogue’ and the ‘Chronographe Étanche’. The styling, 40mm sizing and the fact that it is powered by the legendary Valjoux 72 chronograph calibre all contribute to its desirability.

Condition is of the utmost importance when collecting vintage timepieces, and the rotating, world-time bezel on this ref. E2643 is outstanding. This contrasts with many examples of the Shark to have hit the market in recent years, which have been fitted with scuffed and abraded rotating bezels.

Rolex GMT Master ref. 16758 SARU

Jewelled variants of Rolex’s professional sports watches have always been highly prized — and extremely rare. Finding a ref. 16758 SARU, Rolex’s very first jewelled sports watch and one of the rarest Rolex references of all time, is something for watch collectors to celebrate.

This watch has extravagance written all over it — brilliant, 18k yellow gold case, and diamonds, sapphires and rubies adorning various key components. They combine for an aesthetic that’s outlandish while remaining respectful of traditional Rolex designs, such as the sapphires and rubies that have been set into the bezel of this watch in a pattern that mimics the iconic ‘Pepsi’ bezel insert.

Patek Philippe ref. 725 retailed by Tiffany & Co.

Patek Philippe’s earliest years of production saw the company producing pocket watches, which enabled the brand to master its craft and the art of complication through the development of new calibres at the request of important collectors.

Some collectors have taken a particular interest in Patek’s later pocket watch references, which would have been sold alongside now revered wristwatches. One such reference is the ref. 725, which boasts a perpetual calendar complication, and applied, Arabic numerals in 18k yellow gold.

This relatively modern marvel of pocket-watch production has been preserved incredibly well. It is powered by Patek Philippe’s cal. 17’"170 Q, which features the classic pairing of a perpetual calendar with a moonphase complication. Just below the moonphase aperture are the Patek Philippe signature and the signature of retailer ‘TIFFANY & CO.’, which make it an even more appealing proposition.

Rolex Explorer ref. 1016

Rolex’s Explorer is the original all-purpose, go anywhere, do anything watch — and an attractive one at that. Although the Explorer has long been regarded as the most understated offering in Rolex’s lineup of professional watches, don’t be fooled by its reserved appearance.

The development of the Explorer was inspired by Rolex’s involvement in Sir Edmund Hillary and Tenzing Norgay’s historic ascent of Mount Everest in 1953. The incorporation of rugged technical components and a style that was distilled to the essentials ensured the Explorer became the watch of choice for explorers and adventures for decades to follow.

The ref. 1016 was produced in large numbers for more than 25 years, but finding desirable examples is a challenge. On this watch, scholars will note the presence of both a dial-tracing chapter ring, and a luminous ‘exclamation point’ marking, found just below the six o’clock position.

Cartier Tortue Monopoussoir ref. 2396

Vintage timepieces from Cartier are more popular than ever, which is unsurprising given the manufacturing techniques Cartier uses in its high-end luxury products.

As Cartier increased production of quartz-powered timepieces, the brand still wanted to demonstrate its watchmaking prowess. In 1998 it launched the Collection Privée Cartier Paris, which looked to historic designs for inspiration, and top-tier independent watchmakers including Vianney Halter, Denis Flageollet and F.P. Journe for mechanical know-how.

The essence of this collection is embodied in the ref. 2396, which is effectively a hyper-faithful reissue of the Tortue Monopoussoir of the 1920s. One updated detail of note is the cal. 045MC monopusher movement, which can be admired through the sapphire display caseback. The production of this movement was outsourced to watchmakers whose mastery of their craft is evident in the chronograph’s clutch system, swivel pin mechanism, and intricate finishing throughout.

Omega Speedmaster ref. 105.003 ‘Ed White’

Originally introduced by Omega as a driving chronograph, the Speedmaster was selected by NASA as the space programme’s official wristwatch. Fifty years ago this month, it became the first watch to be worn on the Moon.

The various preceding references show the evolution of the line. The ref. 105.003 ‘Ed White’ is one such example. The last straight-lug Speedmaster, and one of the last references to be powered by the cal. 321, the ‘Ed White’ features larger pushers, along with more legible white hour and minute hands than the ref. 105.002 that preceded it.

Although this reference was not the first watch to be worn on the Moon, it was worn by American astronaut Ed White during the first spacewalk in 1965. NASA’s decision to move forward with Omega for Moon use can perhaps be attributed to the success of White’s mission.